Alibaba cloud microservices (IV) service mesh overview and instance istio

To mention Service Mesh I have to mention microservices , According to Wikipedia

Microservices (Microservices) Is a software architecture style , It is a small functional block focusing on a single responsibility and function (Small Building
Blocks) Based on , Using modularity to compose complex large applications , The use of each functional block has nothing to do with language
(Language-Independent/Language agnostic) Of API Sets communicate with each other

With Google three carriages BIGTABLE,Mapreduce,GFS Appearance , Knock on the door of distributed , Fusing strategy 、 Load balancing 、 The emergence of service discovery , Services have some communication semantics according to business needs , In order to avoid each service developing its own set of communication semantics , There is a micro service framework , for instance Spring Cloud Other framework , They realize the semantic functions required by the distributed system , Like service discovery , Load balancing, etc. , To some extent, the communication details are shielded , So that developers can realize the whole function with less code without considering some problems of communication .
But later , People also found that the microservice framework is not omnipotent , It mainly has the following problems ：
1. Developers need to spend a lot of time learning some details of the microservice framework , Because if something goes wrong , It is difficult to troubleshoot and solve problems without understanding the framework
2. Frameworks that use microservices need to use specific languages , This is different from the original features of microservices ---- It has nothing to do with language

To solve this problem , first generation Service Mesh emerge as the times require
It abstracts the communication of distributed system into a separate layer , It is up to him to realize load balancing 、 Service discovery 、 Certificate authority 、 Surveillance tracking 、 Flow control and other functions required by distributed systems , As a proxy service equivalent to a service , Deployed with services , It completes the request between services through the communication between agents .

Pictured , The blue part is the service grid , If you only look at the blue part , It's easy to understand why it's called “Mesh” Is that right ~

later , For unified management , People have derived the second generation Service Mesh, Developed a centralized control panel , All stand-alone components update the network topology strategy and report the data through the control panel , A very classic example is Istio

Istio It consists of two parts ： Control plane and data plane .

The data plane is the communication plane between businesses . If there is no service grid , The network cannot understand the traffic being sent , Nor can it be based on what type of traffic it is , Or who it comes from , To whom to make any decision .

The service grid uses agents to intercept all network traffic , Allows you to provide a wide range of application aware functions according to the configuration you set .

The agent is deployed with each service you start in the cluster , Or run with a service running on a virtual machine .

The control plane gets the configuration and service views you need , And dynamically program the proxy server , Update them as rules or environments change .

Use Istio Before

Use Istio after ：

Service Mesh Advantages and disadvantages ：
advantage ：
1. Shielding distributed communication complexity
2. Shielding language
3. Transparent to application layer , Don't need to care about

shortcoming ：
1. The communication performance is reduced to a certain extent
2. The overall stability of the service depends on Service Mesh

Pattern：Service Mesh